Core-drilling bit



Dec. 16, 1930. y R. R. cANDl-:E E1- AL 1,785,405

CORE DRILLING BIT Filed oct. 5, 1927 y N V//////// E Ji: ATTORNEY.

Patented Dec. 16, 1930 l UNITED STATES .PATENT OFFICE RAPHAEL ROGERSCANDEE, OF MCEITTRICK, AND OSCAR FRED HARDING, OF

COALINGA, CALIFORNIA conn-Dramma Brr `Application led October 5, 1927.Serial No. 224,197.

This invention relates to deep well drilling tools and more especiallyto a rotary, core cutting tool.

It is highly desirable in the drillingof deep wells that accurate logsbe kept of the actual formation which is encountered, strata by strata.With drills not taking a core the ine cuttings mix with the .circulatingfluid to' such an extent that only rough estimates can be made as to theprobable depth of the strata from the top of the hole and of thethickness of the strata itself. This guess work of logging is verydeficient where the deep strata may each be quite thin.

Various types of core taking drills have been devised and quitesuccessfully used. With these diiculty is experienced in removing thecore.

The present invention has for an object to '20 take a core of anydesired length. A further object is to provide for the ready removal ofthe core from the drill barrel.

Another deficiency of various forms of core drills is the inability toobtain a good specimen when the drill is running through rather softformati on which has the tendency to muck and flow down out of the drillwhen this is pulled out. Therefore another object is to provide meansfor effectively retaining a core specimen of a soft formation.

An additional object is to provide a drill constructed and designed tocut an annular swarth around a dead center Zone and to form a core onthe center and to provide means for by-passing the top of the core infragments out through the side of the drill stem continuously duringoperation of the drill after a predetermined length of core has beencut; it being understood that the core shall be so cast off only incases where the log of the formation is undesired.

There are other objects and advantages and features of construction andcombination, and these will be made manifest in the followingspecification of the herewith illustrated em bodiment; it beingunderstood that modifications, variations and adaptations may beresorted to within the spirit, scope and principle of the invention asit is more directly claimed hereinafter.

. Figure 1 is an axial section of the tool. Figure 2 is a bottom plan ofthe bit. Figure 3 is a side elevation of the bit. Figure 4 is an endview of a core barrel sleeve section.

Figure 5 is an axial section of the assembled barrel of sleeve and cuffparts.

Figure is an end view of one of the split cuffs.

Figure 7 is a centering ring.

Figure 8 is a plan of the core barrel trap.

Figure 9 is an axial section of the trap.

Figure 10 is a detail, on substantially full plan of the core barrelhead scale, of a fragment of the trap showing a mode of mounting a trapfinger.

In its illustrated form the tool includes a stout bottom piece or bitbody 2 having a tapered top pin 3 for attachment to a drill collar orsection 4. The bit body 2 is cen- 70 trally bored and has anintermediate, annular shoulder or ledge 5.

On the bottom face of the bit body 2 is an inner, annular series ofcutters 6 having cutting, end lips 6a and extending inwardly 75 alongthe bit bore and presenting longitudinal cutting edges 6b leaving acentral core of the penetrated formation and which core stands in thebit bore as drilling proceeds.

Extending beyond the bit body 2 is a circle 80 of reaming cutters 7having advance, bottom cuttingedges 7a which are of a length tooverlapthe orbit of the inner cutters 6. The cutters 7 have asubstantial helical pitch on the body 2, receding from the cutting edges7*. 85 As the running drill goesdown the core passes into a trappingmeans in the body 2 which is for the purpose of grappling in the corewhen the drill is pulled from the hole. The trap, as shown, includes acage wall 10 90 provided with inwardly and upwardly inclined spring-leaffingers -ll whose lower ends are riveted at 12 in openings 13 in thecage wall so that the fingers-may lie back flush when the full size bodyof core is em- 954 braced. Then the tool is pulled up the finf i gersspring in and take hold or if the formation is soft the fingers willflex in to form a bottoni for the 'cage and thus retain a very materialport-ionof the penetrated formation.

The fingers, as shown, have a helical pitch reverse from direction ofrotation which is for the purpose of facilitating vrotation of the cagewhile the fingers are engaging a hard core; the fingers having anut-like effeet advancing on the core.

The cut core passes from the bit body 2 and pin 3 up into the hollowcollar 4 and this is provided with a removable core receiver or barrelforming one of the features of this invention. This ,barrel is 'made ofa combination of parts4 constructed and arranged to greatly facilitatethe extraction of the core and includes a ferrule having a base 15seating on top of the trap wall 10 and snugly fitting the body bore soas to close off water passage at aline below a series of water holes 2f.Above the base 15 the ferrule is reduced to a cylinder 15a to form aspace thereabout to the holes 2a for water and is again reduced at 15babove shoulder 15 to snugly receive a short length of tubing or sleeve16 of greater length than the ferrule portion 15".

Any desired length of barrel vmay be built up by abutting a number ofthe sleeves 16, as determined by the length of drill collar 4 ormultiples thereof. The abutted sleeves 16 are detachablyalined bysuitable means here shown as including a line of inside sections orcuffs 17 which'are of resilient metal and split at 17a along one' side.The cuffs have a diameter, when free, greater than the inside diameterof the sleeves 16 and are of' `Acelve the core as itis cut by advance ofthe When the tool is pulled, the sections 16-17 are successively removedfrom the core. To accomplish th1s the sections have pairs of wrenchengaging holes 20, which are soA disposed as to never register andtherefore prevent water liow from sleeve into culi. First, a sleeve ispulled off endwise and lthen the next cuff is pulled to just clear thenext sleeve following which the released cuff will spring open fullyloose about the enveloped core.

The free cuff is then easily pulled endwise ter, non-cutting zone byleaving a core on center and where it is not desired yto retam the corefor log record we provlde vmeans to automatically discard the core bypassing it ofi', in small fragments, and out to one side of the drillWhere it is quickly abraded down by the side wall of the hole duringrotation of the drill.

The discard means shown includes an upper joint 22 having a pin for thecollar and a top box for attachment to the upper drill rbd string (notshown). The joint 22 is chambered to form a Water passage to the collar4 and receives the upper end of the top core barrel sleeve 16. A iue ordeflecting conduit 23 leads from the upper end of the core barrel anddischarges at a side aperture 24. The adjacent ends of the conduit 23and top sleeve 16 are centered and supported by suitable means hereshown as a seat ring 25 having marginal water ports 25a to permitcirculation to the collar 4. The passageway in the conduit 23 pitches atan an le and therefore when the head of the core impinges on the opposedinclined face of the conduit the weight of the whole tool is effectivelyuseful to transversely break 0E the core, if it is of hard stone.

The ring 25 may be of hard metal and form a fulcrum for the core whenthe tool acts on the head of the core to break it olf for deflectioninto the discarding conduit 23.

If the conduit is of removable, renewable installation it can bebuttressed by a backing block 27.

The invention claimed is:

1. In combination, in a drill, a bit body head having a series ofhelical reaming blades with straight bottom cutting edges extendingunder the bottom of the body and a series of bottom cutting blades; thebottom edges of both series of blades .lying in a common plane.

2. In combination, in a `drill, a bit body head having a series ofhelical reaming blades with straight bottom cutting edges extendingunder the bottom of the body for about one-half of the radius and whichedges lie on lines tangential to the bit center and at such an angle asto sweep the cuttings inward toward the c nter and an inner set ofbottom cutters wit\ edges on the same bottom plane of the outer`-blade.

3. In combination, in a drill, a hollow center bit body having a seriesof helical reaming blades with straight bottom cutting edges extendingunder the bottom of the body and which edges lie on lines tangential tothe bit center and positioned to sweep the cuttings inward, and an innerseries of bottom cutting blades with straight bottom edges which lietangential to the center and pitch in a reverse direction to the bottomedges of the rea-ming blades; the plane of each blade of the innerseries lying at an angle of about 60 from the radial line intersectingits nose, and said inner blades overlappin the orbit of the outer bladesand all bla e edges being in a common bottom plane.

4. A drilling tool including a core forming 5 bit, a core trap cageseated therein, a drill' collar detachably secured to the bit stem, astring joint removably attached to the collar, a sectional barrel havinga base feriule bearing against the said ca e and having a top 10 sectionseating in the sald joint and whereby the barrel is clamped in place,and a string of split, self-opening core sleeves lining the barrel inbroken joint relation and friction holding Contact. 15 RAPHAEL ROGERSCANDEE.

OSCAR FRED HARDING.

